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Flash pyrolysis of coals. A new approach of classification
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96/02938 Comparison of biomass and coal char reactivities Sidney, P. et al., Prepr. Pap.-Am. Chem. Soc., Div. Fuel Chem., 1995,40, (3), 694-698. Discusses the experimental approach used to examine biomass and coal char reactivities and extinction behaviours and presents results from captive particle imaging (CPI) experiments. The reactivity as a function of extent of burnout of six types of char particles, two high-rank coal chars, two low-rank coal chars, and two biomass chars, was investigatedusing the CPI apparatus. 96/02939 Controlling NO. emission from high-temperature air-preheat burners with air-staging Dearden, L. M. et al., J. Inst. of Energy, Mar. 1996,69, (478), 23-30. High air-preheat temperature have been used Widely to increase thermal efficienciesin industrial processes. The higher flame temperature generally result in greater NO, emissions. In this study the distribution of temperature and the concentrationsof major chemical species were determined for nominal 586 kW thermal input turbulent-diffusion flame burners firing natural gas and air, and the burners operated in an unstaged or air-staged mode. 96/02940 Deflagratlon to detonation transition In large confined volume of lean hydrogen-air mixtures Dorofeev,S. B. et al., Combustion & Flame, Jan. 1996, 104, (1), 95-110. The results of large-scale experiments on turbulent flame propagation and transition to detonation in a confined volume of lean hydrogen-air mixtures are presented. 96/02941 Design and application of wedge collectors for removal of dust from exit gas Sarkar, H. S. Energy Fuels, 1995, 9, (6), 966-970. Wedge collectors of simple design based on the venturi principle were developed and used in a circulating fluidized bed boiler at the flue path to determine the dust removal efficiency in the exit gas. The efficiency of the collectors was compared with those of other types of mechanical collectors. Describesthe impact on the dust collection efficiency of the collectors due to the increase in the ash content of coal, fluctuation of operational conditions including exit gas velocity, particle size, etc. 96/02942 Development of pressurized coal partial combustor Kajibata, Y. and Harada, E. Nippon Enerugi Gakkaishi, 1995, 74, (8), 705-711. (In Japanese) The paper reviews pressurized coal partial combustion furnaces for gasification and melting and removing ashes in the coal. 96/02943 Development of pressurized coal partial combustor (characteristics of 7 ton/day gasifier with various coal-feed ratios) Fujii, K. et al., Nippon Kikai Gakkai Ronbunshu B-hen, 1995, 61, (587), 2706-2711. (In Japanese) Describes the testing of a pressurized coal partial combustor with a twostage coal supply to elucidate the characteristics of a 7 ton coal/day airblown coal gasifier. 96/02944 The effect of agitation on the char combustion characterIstIcs of large coal particles Malik, A. A. et al., Fuel, Feb. 1996,75, (3), 379-383. To simulate combustionbehaviour in a pilot-scale combustor, a laboratoryscale agitated combustor has been developed which allows burnout and combustion rates for large coal particles to be measured. Particle sizes up to 25 mm can be studied, typical of those used in fixed-bed reactors. Char burnout data were obtained to supplement previously published volatiles release data. 96/02945 Effects of fuel changes. Utilization of coals of different origin In large-scale firing plants Benesch, W. and Schnadt, K. VGB Kraftwerkstech., 1995, 75, (8), 715-721. (In German) The paper discusses the criteria for the evaluation of coal used in dry bottom firing (slag tap pulverized coal firing mostly included) in power generation, The analysis data of several coals are compared, and the in fuel changes affecting plant components are described. 96/02946 An elementary discussion of forward smoldering Buckmaster, J. and Lozinski, D. Combustion & Flame, Feb. 1996, 104, (3), 300-310. The authors describe an elementary model of one-dimensional unsteady forward smoldering, purged of all unncessary physics. Following work of Dosanjh and Pagni, a late time solution is constructed, characterized by two reaction fronts, an exothermic oxidation front, an unusual kind of diffusion flame; and an endothermic pyrolysis front. It is shown that the flame temperature and the ratio of the speeds of the two fronts relative to the solid are independent of the blowing rate, in agreement with data obtained by Ohlemiller and Lucca. The structure of the oxidation front is described in the context of one-step Arrhenius kinetics, and it is shown that leakage of solid reactant through the front is possible, but not leakage of oxygen. An elementary pyrolysis structure is also examined which reduces to the frontal model in a certain limit, and clarifies its nature.
Combustion (burners, combustion systems)
96/02947 European scheme for the classification of gas appliances according to the method of evacuation of the products of combustion (types) BSI 1995, PD.6579.1995, CR.1749, British Standards Institute, 15 pp.
96/02948 Experimental study of the influence of the operatIng variables on natural gas reburnlng efficiency Bilbao, R. et al., Ind. Eng. Chern. Res., 1995, 34, (12), 4531-4539. The influenceof the main operating conditions in the reburningzone using natural gas on the NO, HCN, and NHJ concentrations obtained at the exit of this zone was analyzed. Experiments with a wider range of variable values than those presented in the literature were performed. 96/02949 A flame-controlling continuation method for generating S-curve responses with detailed chemistry Nishioka, M. et al., Combustion & Flame, Feb. 1996, 104, (3), 328-342. A flame-controlling continuation method is formulated for the generation of the ignition-extinction S-curve characteristic of quasi-one-dimensional flames as well as the investigation of the associated flame structure and response, especially for states near the turning points. Using the counterflow premixed and diffusion flames as examples,the method capitalizeson the distinct nature of the profile and location of the scalars of the flame properties, such as the temperature and species concentrations, in response to changes in the flow strain rate. 96/02950 Flash pyrolysis of coals. A new approach of classification Carlsen, L. and Christiansen, J. V. 1. Anal. Appl. Pyrolysis 1995,35, (1), 77-91. Flash pyrolysis-gas chromatography/mass spectrometry constitutes, in combinationwith statistical methods such as principal component analysis and hierarchical cluster analysis, an advantageous technique in an attempt to characterize and classify coals of different origin. Eight coals comprising three from South Africa, two from Australia, and one from U.S.A., Colombia and Indonesia, respectively have been pyrolyzed at 750°C. Results are discussed based on an analogous study applying conventional coal analyses such as elemental analysis, maceral composition, vitrinite reflectance, ash content, etc. 96/02951 Fluidized-bed combustion for energy production from olive cake Abu-Qudais, M. Energy, Mar. 1996,21, (3), 173-178. The author presents an experimental combustion study of olive-oil mill waste (olive cake) in a fluidized bed combustor. Tests were performedin a 13.2-cm i.d. reactor. Cold-flow tests included investigations of the effects of particle-size distribution, fluidization velocity, and bed height. Combustion was carried out by feeding the olive cake in a bed of sand particles. The temperature distribution was found to become fairly uniform 12 cm above the distributorplate. The combustion intensitywas about 812 kg/m2_ h and increasedwith bed height 0.1 and 0.15 m. The combustionefficiency ranged from 86 to 95% and increased with air-flow rate. 96/02952 Forced forward smolder combustion Schult, D. A. et al., Combustion & Flame, Jan. 1996, 104, (I), 1-26. The authors consider porous cylindrical samples closed to the surrounding environment except at the ends, with gas forced into the sample through one of the ends. A smolder wave is initiated at that end and propagates in the same direction as the flow of the gas. They employed asymptoticmethods to find smolder wave solutions with two different structures. Each structure has two interior layers, i.e. regions of relatively rapid variation in temperature separated by longer regions in which the temperature is essentially constant. One layer is that of the combustionreaction, while the other is due to heat transfer between the solid and the gas, The layers propagate with constant, though not necessarily the same, velocity, and are separated by a region of constant high temperature. 96/02953 Gas burner offers less than 10 ppm NO. Altpfart, G. R. and Christman, R. MPS, Modern Power Systems, Nov. 1995, 15, (11), 27, 29-30. Describes a new gas burner developed by Radian Corporation and manufactured by Todd Combustionwhich can attain NO, emissionlevels of less than 10 ppm. By going back to the fundamentals of the combustion process, it has come up with a burner which gives NO, levels previously attainable only with selective catalytic reduction.
96/02954 Generation and decomposition on N20 In the combustIon process Nowak, Wand Janik, M. Gospod. Paliwami Energ., 1995,43, (6), 19-25. (In Polish) A review of Np emission sources in relation to combustion of fuel oil, coal, and fuel gases. Fluidized-bedcombustion was associated with considerable N20 emissions.
Fuel and Energy Abstracts May 1996 205
96/02938 Comparison of biomass and coal char reactivities Sidney, P. et al., Prepr. Pap.-Am. Chem. Soc., Div. Fuel Chem., 1995,40, (3), 694-698. Discusses the experimental approach used to examine biomass and coal char reactivities and extinction behaviours and presents results from captive particle imaging (CPI) experiments. The reactivity as a function of extent of burnout of six types of char particles, two high-rank coal chars, two low-rank coal chars, and two biomass chars, was investigatedusing the CPI apparatus. 96/02939 Controlling NO. emission from high-temperature air-preheat burners with air-staging Dearden, L. M. et al., J. Inst. of Energy, Mar. 1996,69, (478), 23-30. High air-preheat temperature have been used Widely to increase thermal efficienciesin industrial processes. The higher flame temperature generally result in greater NO, emissions. In this study the distribution of temperature and the concentrationsof major chemical species were determined for nominal 586 kW thermal input turbulent-diffusion flame burners firing natural gas and air, and the burners operated in an unstaged or air-staged mode. 96/02940 Deflagratlon to detonation transition In large confined volume of lean hydrogen-air mixtures Dorofeev,S. B. et al., Combustion & Flame, Jan. 1996, 104, (1), 95-110. The results of large-scale experiments on turbulent flame propagation and transition to detonation in a confined volume of lean hydrogen-air mixtures are presented. 96/02941 Design and application of wedge collectors for removal of dust from exit gas Sarkar, H. S. Energy Fuels, 1995, 9, (6), 966-970. Wedge collectors of simple design based on the venturi principle were developed and used in a circulating fluidized bed boiler at the flue path to determine the dust removal efficiency in the exit gas. The efficiency of the collectors was compared with those of other types of mechanical collectors. Describesthe impact on the dust collection efficiency of the collectors due to the increase in the ash content of coal, fluctuation of operational conditions including exit gas velocity, particle size, etc. 96/02942 Development of pressurized coal partial combustor Kajibata, Y. and Harada, E. Nippon Enerugi Gakkaishi, 1995, 74, (8), 705-711. (In Japanese) The paper reviews pressurized coal partial combustion furnaces for gasification and melting and removing ashes in the coal. 96/02943 Development of pressurized coal partial combustor (characteristics of 7 ton/day gasifier with various coal-feed ratios) Fujii, K. et al., Nippon Kikai Gakkai Ronbunshu B-hen, 1995, 61, (587), 2706-2711. (In Japanese) Describes the testing of a pressurized coal partial combustor with a twostage coal supply to elucidate the characteristics of a 7 ton coal/day airblown coal gasifier. 96/02944 The effect of agitation on the char combustion characterIstIcs of large coal particles Malik, A. A. et al., Fuel, Feb. 1996,75, (3), 379-383. To simulate combustionbehaviour in a pilot-scale combustor, a laboratoryscale agitated combustor has been developed which allows burnout and combustion rates for large coal particles to be measured. Particle sizes up to 25 mm can be studied, typical of those used in fixed-bed reactors. Char burnout data were obtained to supplement previously published volatiles release data. 96/02945 Effects of fuel changes. Utilization of coals of different origin In large-scale firing plants Benesch, W. and Schnadt, K. VGB Kraftwerkstech., 1995, 75, (8), 715-721. (In German) The paper discusses the criteria for the evaluation of coal used in dry bottom firing (slag tap pulverized coal firing mostly included) in power generation, The analysis data of several coals are compared, and the in fuel changes affecting plant components are described. 96/02946 An elementary discussion of forward smoldering Buckmaster, J. and Lozinski, D. Combustion & Flame, Feb. 1996, 104, (3), 300-310. The authors describe an elementary model of one-dimensional unsteady forward smoldering, purged of all unncessary physics. Following work of Dosanjh and Pagni, a late time solution is constructed, characterized by two reaction fronts, an exothermic oxidation front, an unusual kind of diffusion flame; and an endothermic pyrolysis front. It is shown that the flame temperature and the ratio of the speeds of the two fronts relative to the solid are independent of the blowing rate, in agreement with data obtained by Ohlemiller and Lucca. The structure of the oxidation front is described in the context of one-step Arrhenius kinetics, and it is shown that leakage of solid reactant through the front is possible, but not leakage of oxygen. An elementary pyrolysis structure is also examined which reduces to the frontal model in a certain limit, and clarifies its nature.
Combustion (burners, combustion systems)
96/02947 European scheme for the classification of gas appliances according to the method of evacuation of the products of combustion (types) BSI 1995, PD.6579.1995, CR.1749, British Standards Institute, 15 pp.
96/02948 Experimental study of the influence of the operatIng variables on natural gas reburnlng efficiency Bilbao, R. et al., Ind. Eng. Chern. Res., 1995, 34, (12), 4531-4539. The influenceof the main operating conditions in the reburningzone using natural gas on the NO, HCN, and NHJ concentrations obtained at the exit of this zone was analyzed. Experiments with a wider range of variable values than those presented in the literature were performed. 96/02949 A flame-controlling continuation method for generating S-curve responses with detailed chemistry Nishioka, M. et al., Combustion & Flame, Feb. 1996, 104, (3), 328-342. A flame-controlling continuation method is formulated for the generation of the ignition-extinction S-curve characteristic of quasi-one-dimensional flames as well as the investigation of the associated flame structure and response, especially for states near the turning points. Using the counterflow premixed and diffusion flames as examples,the method capitalizeson the distinct nature of the profile and location of the scalars of the flame properties, such as the temperature and species concentrations, in response to changes in the flow strain rate. 96/02950 Flash pyrolysis of coals. A new approach of classification Carlsen, L. and Christiansen, J. V. 1. Anal. Appl. Pyrolysis 1995,35, (1), 77-91. Flash pyrolysis-gas chromatography/mass spectrometry constitutes, in combinationwith statistical methods such as principal component analysis and hierarchical cluster analysis, an advantageous technique in an attempt to characterize and classify coals of different origin. Eight coals comprising three from South Africa, two from Australia, and one from U.S.A., Colombia and Indonesia, respectively have been pyrolyzed at 750°C. Results are discussed based on an analogous study applying conventional coal analyses such as elemental analysis, maceral composition, vitrinite reflectance, ash content, etc. 96/02951 Fluidized-bed combustion for energy production from olive cake Abu-Qudais, M. Energy, Mar. 1996,21, (3), 173-178. The author presents an experimental combustion study of olive-oil mill waste (olive cake) in a fluidized bed combustor. Tests were performedin a 13.2-cm i.d. reactor. Cold-flow tests included investigations of the effects of particle-size distribution, fluidization velocity, and bed height. Combustion was carried out by feeding the olive cake in a bed of sand particles. The temperature distribution was found to become fairly uniform 12 cm above the distributorplate. The combustion intensitywas about 812 kg/m2_ h and increasedwith bed height 0.1 and 0.15 m. The combustionefficiency ranged from 86 to 95% and increased with air-flow rate. 96/02952 Forced forward smolder combustion Schult, D. A. et al., Combustion & Flame, Jan. 1996, 104, (I), 1-26. The authors consider porous cylindrical samples closed to the surrounding environment except at the ends, with gas forced into the sample through one of the ends. A smolder wave is initiated at that end and propagates in the same direction as the flow of the gas. They employed asymptoticmethods to find smolder wave solutions with two different structures. Each structure has two interior layers, i.e. regions of relatively rapid variation in temperature separated by longer regions in which the temperature is essentially constant. One layer is that of the combustionreaction, while the other is due to heat transfer between the solid and the gas, The layers propagate with constant, though not necessarily the same, velocity, and are separated by a region of constant high temperature. 96/02953 Gas burner offers less than 10 ppm NO. Altpfart, G. R. and Christman, R. MPS, Modern Power Systems, Nov. 1995, 15, (11), 27, 29-30. Describes a new gas burner developed by Radian Corporation and manufactured by Todd Combustionwhich can attain NO, emissionlevels of less than 10 ppm. By going back to the fundamentals of the combustion process, it has come up with a burner which gives NO, levels previously attainable only with selective catalytic reduction.
96/02954 Generation and decomposition on N20 In the combustIon process Nowak, Wand Janik, M. Gospod. Paliwami Energ., 1995,43, (6), 19-25. (In Polish) A review of Np emission sources in relation to combustion of fuel oil, coal, and fuel gases. Fluidized-bedcombustion was associated with considerable N20 emissions.
Fuel and Energy Abstracts May 1996 205